Wood anatomy features of eight taxa (four species) of the genus Fraxinus L. indigenous to Turkey were examined. Wood samples were collected from different altitudes of their natural growth areas. Data were gathered on quantitative anatomical features such as tangential and radial vessel diameters, number of vessels per mm(2), length of vessel elements, fibers (lengths, widths, thickness of cell walls, lumen diameters), number of rays per mm, and ray width and height. By using vessel member features, the vulnerability ratio (vessel diameter divided by number of vessels per mm(2)) and mesomorphy value (vulnerability ratio multiplied by vessel elements length) were calculated. Stem diameter, plant height, altitude of the locality, and plant age were determined for each individual tree. Anatomic and nonanatomic features (altitude, height and diameter of plant, annual ring number) were correlated, and the effects of these nonanatomic factors on anatomic features were examined at intraspecific and interspecific levels, and variations of wood anatomy were determined. In the trends of genera and taxa, there is a negative correlation between altitude and radial and tangential diameter of vessel, length of vessel elements, fiber lengths and widths, fiber of lumen diameters, and ray widths and height. When altitude increases, the dimensions of these elements decrease; in contrast, the number of vessels per mm(2) and number of rays per mm increases with altitude.